/*  mbed Microcontroller Library
    Copyright (c) 2006-2013 ARM Limited

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
#include "LocalFileSystem.h"

#if DEVICE_LOCALFILESYSTEM

#include "semihost_api.h"
#include <string.h>
#include <stdio.h>

namespace mbed {

    /* Extension to FINFO type defined in RTL.h (in Keil RL) - adds 'create time'. */
    typedef struct {
        unsigned char  hr;   /* Hours    [0..23]                  */
        unsigned char  min;  /* Minutes  [0..59]                  */
        unsigned char  sec;  /* Seconds  [0..59]                  */
        unsigned char  day;  /* Day      [1..31]                  */
        unsigned char  mon;  /* Month    [1..12]                  */
        unsigned short year; /* Year     [1980..2107]             */
    } FTIME;

    typedef struct {         /* File Search info record           */
        char  name[32];      /* File name                         */
        long  size;          /* File size in bytes                */
        int   fileID;        /* System File Identification        */
        FTIME create_time;   /* Date & time file was created      */
        FTIME write_time;    /* Date & time of last write         */
    } XFINFO;

#define RESERVED_FOR_USER_APPLICATIONS (0x100) /* 0x100 - 0x1ff */
#define USR_XFFIND (RESERVED_FOR_USER_APPLICATIONS + 0)

    static int xffind(const char* pattern, XFINFO* info) {
        unsigned param[4];

        param[0] = (unsigned long)pattern;
        param[1] = (unsigned long)strlen(pattern);
        param[2] = (unsigned long)info;
        param[3] = (unsigned long)sizeof(XFINFO);

        return __semihost(USR_XFFIND, param);
    }

#define OPEN_R          0
#define OPEN_B          1
#define OPEN_PLUS       2
#define OPEN_W          4
#define OPEN_A          8
#define OPEN_INVALID   -1

    int posix_to_semihost_open_flags(int flags) {
        /* POSIX flags -> semihosting open mode */
        int openmode;
        if (flags & O_RDWR) {
            /* a plus mode */
            openmode = OPEN_PLUS;
            if (flags & O_APPEND) {
                openmode |= OPEN_A;
            } else if (flags & O_TRUNC) {
                openmode |= OPEN_W;
            } else {
                openmode |= OPEN_R;
            }
        } else if (flags & O_WRONLY) {
            /* write or append */
            if (flags & O_APPEND) {
                openmode = OPEN_A;
            } else {
                openmode = OPEN_W;
            }
        } else if (flags == O_RDONLY) {
            /* read mode */
            openmode = OPEN_R;
        } else {
            /* invalid flags */
            openmode = OPEN_INVALID;
        }

        return openmode;
    }

    FILEHANDLE local_file_open(const char* name, int flags) {
        int openmode = posix_to_semihost_open_flags(flags);
        if (openmode == OPEN_INVALID) {
            return (FILEHANDLE)NULL;
        }

        FILEHANDLE fh = semihost_open(name, openmode);
        if (fh == -1) {
            return (FILEHANDLE)NULL;
        }

        return fh;
    }

    LocalFileHandle::LocalFileHandle(FILEHANDLE fh) : _fh(fh), pos(0) {
    }

    int LocalFileHandle::close() {
        int retval = semihost_close(_fh);
        delete this;
        return retval;
    }

    ssize_t LocalFileHandle::write(const void* buffer, size_t length) {
        ssize_t n = semihost_write(_fh, (const unsigned char*)buffer, length, 0); // number of characters not written
        n = length - n; // number of characters written
        pos += n;
        return n;
    }

    ssize_t LocalFileHandle::read(void* buffer, size_t length) {
        ssize_t n = semihost_read(_fh, (unsigned char*)buffer, length, 0); // number of characters not read
        n = length - n; // number of characters read
        pos += n;
        return n;
    }

    int LocalFileHandle::isatty() {
        return semihost_istty(_fh);
    }

    off_t LocalFileHandle::lseek(off_t position, int whence) {
        if (whence == SEEK_CUR) {
            position += pos;
        } else if (whence == SEEK_END) {
            position += semihost_flen(_fh);
        } /* otherwise SEEK_SET, so position is fine */

        /* Always seems to return -1, so just ignore for now. */
        semihost_seek(_fh, position);
        pos = position;
        return position;
    }

    int LocalFileHandle::fsync() {
        return semihost_ensure(_fh);
    }

    off_t LocalFileHandle::flen() {
        return semihost_flen(_fh);
    }

    class LocalDirHandle : public DirHandle {

      public:
        struct dirent cur_entry;
        XFINFO info;

        LocalDirHandle() : cur_entry(), info() {
        }

        virtual int closedir() {
            delete this;
            return 0;
        }

        virtual struct dirent* readdir() {
            if (xffind("*", &info) != 0) {
                return NULL;
            }
            memcpy(cur_entry.d_name, info.name, sizeof(info.name));
            return &cur_entry;
        }

        virtual void rewinddir() {
            info.fileID = 0;
        }

        virtual off_t telldir() {
            return info.fileID;
        }

        virtual void seekdir(off_t offset) {
            info.fileID = offset;
        }
    };

    FileHandle* LocalFileSystem::open(const char* name, int flags) {
        /* reject filenames with / in them */
        for (const char* tmp = name; *tmp; tmp++) {
            if (*tmp == '/') {
                return NULL;
            }
        }

        int openmode = posix_to_semihost_open_flags(flags);
        if (openmode == OPEN_INVALID) {
            return NULL;
        }

        FILEHANDLE fh = semihost_open(name, openmode);
        if (fh == -1) {
            return NULL;
        }
        return new LocalFileHandle(fh);
    }

    int LocalFileSystem::remove(const char* filename) {
        return semihost_remove(filename);
    }

    DirHandle* LocalFileSystem::opendir(const char* name) {
        return new LocalDirHandle();
    }

} // namespace mbed

#endif
